Solving the problem of unsafe sanitation will create a new multi-billion-dollar business opportunity, Bill Gates, founder of Microsoft and co-chair of the Bill & Melinda Gates Foundation, said in his speech at the opening of the Reinvented Toilet Expo on Tuesday in Beijing.

The three-day event is billed as showcasing the most significant advances in sanitation in nearly 200 years, offering radically new and pilot-tested approaches to sanitation that will provide effective alternatives for collecting, managing and treating human waste.

Sanitation problem: bigger than imagined

In 2015, 61 percent of the global population, or 4.5 billion people lacked safely managed sanitation services, according to a report jointly published by the World Health Organization and the United Nations International Children's Emergency Fund last year.

Gates illustrated the problem with a beaker of human feces in his hand, saying that in places without safe sanitation, there is a lot more than one small beaker's worth in the environment.

This small amount of feces could contain as many as 200 trillion rotavirus cells, 20 billion Shigella bacteria and 100,000 parasitic worm eggs, which may cause diseases that can claim the lives of nearly 500,000 children under the age of five every year, he said.

"Unsafe sanitation also puts a huge economic burden on countries that can least afford it", Gates said. "Globally, it costs an estimated US$223 billion a year in the form of higher health costs and lost productivity and wages."

He said that inaction will make the problem worse as population growth, urbanization, and water scarcity over the next few decades will add to the difficulty for cities in Africa and Asia, which are already struggling with inadequate sanitation systems, to break the cycle of disease and poverty associated with unsafe sanitation.

Technological breakthroughs

Having witnessed "a dimension of poverty" where children were playing in lanes filled with human waste and pit latrines were emptied by hand…, in 2009 Gates came up with the idea of developing a more affordable approach that could kill pathogens and keep pace with the needs of fast-growing urban areas.

He said that over the past seven years, the foundation has invested more than US$200 million working with partners to develop a new generation of non-sewered sanitation technologies.

Now, a small-scale treatment plant has been developed to process fecal sludge and biosolids from pit latrines, septic tank and sewers.

The self-powered technology called Omni-Processor is designed to take in human waste, kill dangerous pathogens, and convert the resulting materials into products with potential commercial value, such as clean water, electricity and fertilizer.

Another technological breakthrough is the Reinvented Toilet, a pathogen-killing and self-contained toilet with a tiny treatment plant built in.

Gates said that the toilet "is actually a collection of innovative technologies that use different approaches to break down human waste and destroy germs—leaving behind clean water and solids that can be used as fertilizer . . . or that can be disposed of safely outdoors without further treatment."

Scaling up commercialization for greater good

Gates said that the new generation of reinvented toilets alone are estimated to offer a US$6 billion a year global business opportunity by 2030.

"If you add the Omni-Processor and related products and services, the market potential for decentralized sanitation solutions is likely much larger," he said, calling for the efforts from various parties to scale the technological advances for greater public good.

In fact, there has been positive momentum among governments, private sectors and financial and development institutions.

Gates said that a growing number of countries are embracing a smart approach to safe sanitation, such as India, South Africa, Senegal, Bangladesh and Nepal, and more than 20 companies are business-ready with innovative, non-sewered sanitation products.

The World Bank, the Asian Development Bank and the African Development Bank are announcing commitments with the potential to unlock US$2.5 billion in financing for City-Wide Inclusive Sanitation projects, he said.

He also hailed China's progress in improving health and sanitation for hundreds of millions of people. "China's Toilet Revolution and its action plan for accelerating progress on safe sanitation underscores its potential as a launch market for non-sewered sanitation solutions."

At the end of his speech, Gates expressed his commitment to making a sanitation revolution happen. "It's no longer a question of if we can do it. It's a question of how quickly this new category of off-grid solutions will scale. We don't know exactly how long that will take, but we do know it can't happen fast enough."